A gear is a rotating machine part having cut teeth, which mesh with another toothed part to transmit torque. Geared devices can change the speed, torque, and direction of the power source. Gears almos...

A gear is a rotating machine part having cut teeth, which mesh with another toothed part to transmit torque. Geared devices can change the speed, torque, and direction of the power source. Gears almost always produce a change in torque, giving a mechanical advantage through their gear ratio and can also be considered a simple machine..